of flint



A. CHAMPION AND A. SCHMIDT.

SPARK PLUG.

APPLICATION FIL ED SEPT- 25; I9I8.

Patented Apr. 19, 1921.

INVENTORS (IIIJQPI: Champion By @IIIDQTJCQCILTYLICII W ATTORNEY.-

A UNITEDTSTATES PATENT OFFICE.

ALBERT CHA PIoN AND ALBERT SCHMIDT, I or FLINT, MICHIGAN, ASSIGNORS oCHAMPION IGNITION COMPANY, or FLINT, MICHIGAN, A CORPORATION OF MICH-IGAN. A

SPARK-PLUG.

Specification of Letters Patent. Patented Apr, 19, 1921.

Application filed September 25, 1918. Serial No. 255,582.

To all whom it may comm;

Be it known that We, ALBERT CHAMPION and ALBERT SCHMIDT, citizens of theUnited States, both residents of Flint, Genesee county, State ofMichigan, have invented certain new and useful Improvements inSpark-Plugs, of, which the following is a specification.

Theinvention relates to improvements in spark plugs as described in thepresent specification and illustrated in the accompanying drawing thatforms part thereof. One of the objects of the invention is to devise aspark plug which will be of simple construction and durable inoperation.

Another object of the invention is to devise a spark lug which shallhave the electrodeexposed to the products of combustion effectivelyinsulated by a fireproof insulator, which shall be further protected andcushioned from fracture clue to anyvibration or shock. p 7

Another object of the invention is to devise a spark plug, the parts ofwhich can be readilyassembled and clamped together as a unit with afeeling of assurance that the 1 several insulator parts are in perfectcondition. I Y

Another object of the invention is to devise a sparkiplug having thecentral or sparking electrode properly proportioned to conduct heat fromthe firi-ng end and to further, provide a roper insulationand sealingelectrode and surrounding parts. v v 7 Another object of the inventionis to devise a spark plug in which the several insulator parts may bemade of simple form and readily assembled.

'These' andother objects will more-clearly appear from the followingdescription taken in connection with the accompanying draw- I in Thedrawing shows a vertical sectional view of the spark plug. 1' v YReferrin to the drawing, 10 1s the shell of the spar plug, whichmay beof any deterior bore 11 and the lower part thereof forming a firingchamber with the interior bore 12, the exterior of the firing chamberbeing threaded as at 13 andthe exterior of the insulator chamber beingformed with an extending portion, as at p 14, to receive a wrench.

The interior bore of the shell, where the chamber 11 is reduced to thechamber 12, is

' formed with the gasket seat 15 on which a gasket l6 formed of mica orother suitable material is placed preparatory to seating thereon theinsulator 17, saidinsulator 17 being protected around the sides thereofby a 7 cylinder of mica 18 which forms a lining for the insulatorchamber 11.

tomar to receive a terminal nut hereinafter descri ed.

The electrode 19 between the flange 20 and the top ofthe insulator 17 isprovided I with a gasket or suitable compression washer 23, and also hasthe upper end thereof covered with the mica tube 24.

The space in theinsulator chamber 11 above the flange 20 of theelectrode 19 is filled with mica washers 25, and covered with a followerplate 26 formed of metal and clamped firmly in position by any suitablemeans, that shown in the drawing being the flange 27 turned over theplatefrom the upper edge of the shell 10.

The shell 10 is capped by a dome member 28,. having a central orifice 29therethrough through which the electrode 19 extends, the terminal nut 30being threaded onto the end of the electrode and firmly holding the dome28 in position. v v

The operation of the plug whereby a spark is caused to jump between theterminals formed by the extreme lower end of the lower part 21 of thecentral electrode 19 and another electrode as 31 extending from theshell, will of course be well understood, and it is particularly desiredto point out the peculiar nesting of the insulator element 17 in theshell.

It has been shown in actual practice that mica forms-an excellentinsulator for the hightension current used in spark plugs, but when themica is subjected to the heat and fire of the combustible gases withinthe 7 gasket material for sealing purposes, and

that the porcelain which'is exposed to the heat and fire of thecombustion gases and forms the insulation for the lower and sparking endof the central electrode is comparatively very short and of block formto withstand all vibrations or shocks which will be received.

The insulator is further cushioned by the gasket or washer 23 and allthe clamping action for securing the parts firmly together is directlyreceived by the follower plate 26 and transmitted through the pile ofmica discs 25 so that the lower and allimportant insulating member 17 isheld with a degree of resiliency sufiicient to keep it whole andgastight.

The pile of mica discs is also the only efiicient means for filling thespace between the upper part of the central electrode and the shell asthe upper end of the electrode is ,made comparatively large to properlyconduct heat away from the lower sparking end and this large electrodewill not permit suflicient space for the use of a materialsuch asporcelain and have the same sufficiently strong to properly sustain thenecessary sealing pressures. j

It will of course be understood that the mica cylinder 18 prevents anyshort-circuiting of the current from the flange 20 to the f shell 10,and likewise the mica tube 24: prevents any short-circuiting from theelctrode to the nearest point of the shell as atthe flange 27.

The dome 28 as described is a desirable finish for the upper part of theplug though it will of course be understood that the same is notnecessary to asuccessful operation of the plug. 7

It will be obvious to thoseskilled in the art that many modificationsand changes may be made without departing from the spirit and scope ofthe invention.

Having thus described our invention what we claim as new and desire tosecure by Letters Patent is end of said shell, and means for retainingplace within said insulators and said electrode in said shell.

2. -A spark plug comprisinga shell, a central electrode, a porcelaininsulator tip supported in said shell about the sparkin end of saidelectrode, a mica insulator filling within said shell above saidporcelain insulator, a metal follower plate within said shell above saidmica, and means for retaining said follower plate, said insulators andsaid electrode in said shell.

3. A spark plug comprising a shell, a central electrode, a porcelaininsulator tip supported in said shell about the sparkin end of saidelectrode, a mica insulator filling within said shell above saidporcelain insulator, and a metal follower plate within said shell abovesaid mica and pressed upon by an inturned flange of said shell tocompress said mica and porcelain insulators firmly into position in saidshell.

4:. A spark plug comprising a shell having a tubular hnmg of insulatingmaterial, a central electrode having atubul'ar covering of insulatingmaterial, .an insulator tip sup-' ported within the lower portion ofsaid shell about the sparking end of said electrode, a second insulatorfilling the space within said shell above said first mentioned insulatorand the upper end of whichlies below the upper end of said shell, andmeans for retaining place Within said insulators and said electrode insaid shell.

5. In a s ark plug, an electrode havin a tube of mica about the upperend an a porcelain insulator tip about the lower end thereof, a micainsulator body located above said porcelain insulator and surroundingsaid mica tube, and a cylinder of mica inclosinIg said mica andporcelain insulators.

6. n a spark plug, an electrode having a lateral flange intermediate thelengththereof dividing the same into an upper end and a sparking end, atube of insulatin material about the upper end and a porce ain insulatortip about the sparking end ofsaid electrode, a' second insulator locatedabove said porcelain insulator and surrounding said tube and betweenwhich two insulators said flange lies, and a cylinder of insulatingmaterial inclosing said two insulators and said flange. Y

7. In a device of the class described, in combination, 'a metallic shellhavin a bore therethrough opening into a fire dliamber, a fire proofsparkin point insulator element fitting said bore ant closing thesame atthe fire chamber end, a non-fract'urable insulator arranged in said boreand located "above said fire proof insulator and terminat ing below theupper end of said shell, and an electrode extending through passagesprovided in said two insulators.

8. Ina device of the class described, in

two insulators, and a dome surrounding the upper end of said electrodeand through which said upper end extends, and the lower end of saidshell.

9. A spark plug comprisin a shell having an insulator chamber an a firechamber of reduced cross section, a cylinder of mica lining saidinsulator chamber, a fire proof sparking point insulator fitted in saidinsulator chamber and projecting into said fire chamber, an electrodehaving a lateral flange intermediate the length thereof abut ting saidfire proof insulator and a sparking end extendin therethrough into saidfire chamber, a tu e of mica inclosing the upper end of said electrode,a body of nonfracturable insulating material filling said insulatorchamber between said tube and cylinder and retained therein in acompressed state, and a dome member capping said shell and having acentral orifice throu h which said electrode extends.

10. n a spark plug, an electrode having the lower end thereof insulatedby a fire proof insulator and the upper end thereof insulated by anon-fracturable insulator, said insulators being both surrounded by anon-fracturable insulating member which is in contact with a metallicsupporting element. end of which dome abuts against the upper 11. Aspark plug comprising a hollow metallic shell, an insulator ofcomparatively high heat resisting qualities supported in said shelladjacent the'lower end thereof, a central electrode supported in saidinsulator and having a comparatively large upper portion, and aninsulator filling of nonfracturable material compressed into the spacebetween the upper end of said electrode and said shell and whichinsulator filllllllg terminates below the upper end of said s ell.

In testimony whereof, we aflix our signa-

